Thin down and breakup of a largeZ cosmic ray primary

Abstract

A highZ primary cosmic ray particle is observed in G-5 emulsion exposed in Texas at an altitude of 104 000 ft. Thin down measurements indicate a value ofZ between 24 and 40. The thin down is accompanied by a partial breakup which permits an interesting determination of the charge on the primary, and suggests that the charge on the primary is between 35 and 40.